[all-commits] [llvm/llvm-project] 2dab55: [mlir][spirv] Change numeric constant's bit-extens...

[Md Abdullah Shahneous Bari via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 2dab551d649cb57127f7b3bea183f069883d76e4
      https://github.com/llvm/llvm-project/commit/2dab551d649cb57127f7b3bea183f069883d76e4
  Author: Md Abdullah Shahneous Bari <Md.Abdullah.Shahneous.Bari at intel.com>
  Date:   2023-06-05 (Mon, 05 Jun 2023)

  Changed paths:
    M mlir/lib/Target/SPIRV/Serialization/Serializer.cpp
    M mlir/test/Target/SPIRV/constant.mlir
    M mlir/unittests/Dialect/SPIRV/SerializationTest.cpp

  Log Message:
  -----------
  [mlir][spirv] Change numeric constant's bit-extension decision to be based on type

Integer constants with bit width less than a word (e.g., i8, i16)
should be bit extended based on its type to be SPIR-V spec-compliant.
Previously, the decision was based on the most significant bit of the
value which ignores the signless semantics and causes problems when
interfacing with SPIR-V tools.

Dealing with numeric literals: the SPIR-V spec says, "If a numeric
type’s bit width is less than 32-bits, the value appears in the
low-order bits of the word, and the high-order bits must be 0 for
a floating-point type or integer type with Signedness of 0, or sign
extended for an integer type with a Signedness of 1 (similarly for the
remaining bits of widths larger than 32 bits but not a multiple of 32
bits)."

Therefore, signless integers (e.g., i8, i16) and unsigned integers
should be 0-extended, and signed integers (e.g., si8, si16) should be
sign-extended.

Patch By: mshahneo
Reviewed By: kuhar

Differential Revision: https://reviews.llvm.org/D151767